#include <assert.h>
#include <algorithm>

#ifdef _WIN32
#  include <malloc.h>
#else
#  include <alloca.h>
#endif

#include "TracyPrint.hpp"
#include "TracyImGui.hpp"

namespace tracy
{

void DrawZigZag( ImDrawList* draw, const ImVec2& wpos, double start, double end, double h, uint32_t color, float thickness )
{
    const auto dpos = wpos + ImVec2( 0.5f, 0.5f );

    const auto spanSz = end - start;
    if( spanSz <= h * 0.5 )
    {
        DrawLine( draw, dpos + ImVec2( start, 0 ), wpos + ImVec2( start + spanSz, round( -spanSz ) ), color, thickness );
        return;
    }

    const auto h05 = round( h * 0.5 );
    const auto h2 = h*2;
    int steps = int( ( end - start ) / h2 );

    auto path = (ImVec2*)alloca( sizeof( ImVec2 ) * ( 2 * steps + 4 ) );
    auto ptr = path;

    *ptr++ = dpos + ImVec2( start, 0 );
    *ptr++ = dpos + ImVec2( start + h05, -h05 );
    start += h05;

    while( steps-- )
    {
        *ptr++ = dpos + ImVec2( start + h,   h05 );
        *ptr++ = dpos + ImVec2( start + h2, -h05 );
        start += h2;
    }

    if( end - start <= h )
    {
        const auto span = end - start;
        *ptr++ = dpos + ImVec2( start + span, round( span - h*0.5 ) );
    }
    else
    {
        const auto span = end - start - h;
        *ptr++ = dpos + ImVec2( start + h, h05 );
        *ptr++ = dpos + ImVec2( start + h + span, round( h*0.5 - span ) );
    }

    draw->AddPolyline( path, ptr - path, color, 0, thickness );
}

void DrawStripedRect( ImDrawList* draw, const ImVec2& wpos, double x0, double y0, double x1, double y1, double sw, uint32_t color, bool fix_stripes_in_screen_space, bool inverted )
{
    assert( x1 >= x0 );
    assert( y1 >= y0 );
    assert( sw > 0 );

    const auto ww = ImGui::GetItemRectSize().x;
    if( x0 > ww || x1 < 0 ) return;

    if( x1 - x0 > ww )
    {
        x0 = std::max<double>( 0, x0 );
        x1 = std::min<double>( ww, x1 );
    }

    x0 += wpos.x;
    x1 += wpos.x;

    ImGui::PushClipRect( ImVec2( x0, y0 ), ImVec2( x1, y1 ), true );

    const auto rw = x1 - x0;
    const auto rh = y1 - y0;
    const auto cnt = int( ( rh + rw + sw*2 ) / ( sw*2 ) );
    auto v0 = ImVec2( x0, y0 - rw );

    if ( fix_stripes_in_screen_space )
    {
        const auto window_height = double( ImGui::GetWindowHeight() );
        const auto flipped_v0y = window_height - v0.y; //we transform into a y-is-up coordinate space to achieve upper-left to lower-right stripes. If we didn't, we would calculate values for lower-left to upper-right

        const auto manhattan_distance = x0 + flipped_v0y;
        const auto in_multiples_of_2_times_sw = int( manhattan_distance / ( sw*2 ) );

        const auto floored_manhatten_distance = double( in_multiples_of_2_times_sw*sw*2 ); //floor in terms of 2 * stripe width

        const auto corrected_flipped_v0y = ( floored_manhatten_distance - x0 ); //the corrected (floored) y respects the position of the stripes
        v0.y = window_height - corrected_flipped_v0y - double( inverted*sw ); //transform back into y-is-down imgui space
    }

    for( int i=0; i<cnt; i++ )
    {
        draw->PathLineTo( v0 + ImVec2( 0, i*sw*2 ) );
        draw->PathLineTo( v0 + ImVec2( rw, i*sw*2 + rw ) );
        draw->PathLineTo( v0 + ImVec2( rw, i*sw*2 + rw + sw ) );
        draw->PathLineTo( v0 + ImVec2( 0, i*sw*2 + sw ) );
        draw->PathFillConvex( color );
    }

    ImGui::PopClipRect();
}

void DrawHistogramMinMaxLabel( ImDrawList* draw, int64_t tmin, int64_t tmax, ImVec2 wpos, float w, float ty )
{
    const auto dpos = wpos + ImVec2( 0.5f, 0.5f );
    const auto ty15 = round( ty * 1.5f );
    const auto mintxt = TimeToString( tmin );
    const auto maxtxt = TimeToString( tmax );
    const auto maxsz = ImGui::CalcTextSize( maxtxt ).x;
    DrawLine( draw, dpos, dpos + ImVec2( 0, ty15 ), 0x66FFFFFF );
    DrawLine( draw, dpos + ImVec2( w-1, 0 ), dpos + ImVec2( w-1, ty15 ), 0x66FFFFFF );
    draw->AddText( wpos + ImVec2( 0, ty15 ), 0x66FFFFFF, mintxt );
    draw->AddText( wpos + ImVec2( w-1-maxsz, ty15 ), 0x66FFFFFF, maxtxt );

    char range[64];
    sprintf( range, ICON_FA_LONG_ARROW_ALT_LEFT " %s " ICON_FA_LONG_ARROW_ALT_RIGHT, TimeToString( tmax - tmin ) );

    const auto rsz = ImGui::CalcTextSize( range ).x;
    draw->AddText( wpos + ImVec2( round( (w-1-rsz) * 0.5 ), ty15 ), 0x66FFFFFF, range );
}

}
